The mayor of London expressed sympathy for the capital's taxi drivers in their fight against American cab-hire app Uber.

Speaking at the launch of the London Tech Week, Boris Johnson told reporters that it would be "difficult" for him to ban Uber "without the risk of a judicial review", but that he could see the point the taxi drivers were making in their protests earlier in June.

"I think it's a very difficult [question]," he said. "We've gone to the high court to get a ruling on this, and the issue is basically: is the driver's mobile in the cab equivalent to a taxi meter? I can see why m'learned friends might think that it is, because it's receiving data about, or it's calculating, the distance and time and the fare.

"And there are other lawyers who say that it isn't, and that was the advice of the counsel to TfL. And so we've got a legal problem."

London's black cab drivers pushed the capital to a standstill last Wednesday, over Transport for London's refusal to stop Uber using its smartphone app to calculate fares based on distance and time taken – something they say infringes their right to be the sole users of taxi meters in the city.

But other cabbies say that the issue goes deeper than just Uber, and in fact relates to TfL's handling of minicabs in general.

In a blog post last week, driver Richard Cudlip conceded that "as a trade we failed to get our message across" but suggested that the real issues are about safety in minicabs, slow issuing (and reissuing) of black cab licences, a failure to prevent minicabs from illegally touting for business, and a lack of space outside key London tourist destinations.

'The truth shall set you free'

Johnson also addressed the recent ruling by the ECJ on the "right to be forgotten," saying he could see how it was "practically possible".

"I am on the side, basically, of history, free speech, of people's right to know what's going on in the world, and I think there are worse things in life than to have your Wikipedia entry mildly inaccurate – as mine is, at several crucial points," he said.

"The internet is a wonderful thing. It allows us to know what's going on. I don't want to see people effectively going through it to weed out the truth. The truth shall set you free, that is my view."

On other tech issues, however, Johnson was less forthcoming. Asked if Londoners would see driverless cars on their streets, he said "You already have driverless cars on the streets of London – parked. And we have no plans to remove them."